The last undated gilt was issued in October 1946, shortly after the end of World War Two.

During the budget, in March, George Osborne heralded the potential for the new gilts as a sign of the strength of the British economy.

Speaking of the Treasury's recent ability to borrow money more cheaply than at any previous time in the 400-year history of the Treasury, he said: "This reflects the confidence investors have in Britain's ability to pay its way."

"I now want to test whether we can we can extend these benefits further into the future and diversify our portfolio."

The DMO consultation reflects that the agency is not yet convinced of the need for the long-dated bonds.

"The Government will also give due consideration to the risks associated with fixing the rate of interest payable on debt over such a period," it reads.

It also says that before a final decision is taken, the Government would have to be sure that the cost of financing would be reduced.

A senior banker said that there was little demand for such products, and he expected the consultation, which ends on August 17, to highlight that.

A spokesman for the National Association of Pension Funds (NAPF) said it was aware of the consultation and planned to respond.

Joanne Segars, chief executive of the NAPF, who questioned the rationale for the long-dated bonds shortly after the budget, said: "Most final salary pension schemes are now closed to new joiners and are becoming more mature. Their liabilities are long-term, but not that long-term."

"Pension funds are looking for 30, 40 and 50-year index-linked debt, and would much rather the Government issue more of those."

She also questioned that even if a 100-year bond did exist, whether it would yield a strong enough return for investors.